Formation Mechanism of Hydrous Zirconia Particles Produced by Hydrolysis of ZrOCl2Solutions: IV, Effects of ZrOCl2Concentration and Reaction Temperature
Formation Mechanism of Hydrous Zirconia Particles Produced by Hydrolysis of ZrOCl2Solutions: IV, Effects of ZrOCl2Concentration and Reaction Temperature
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ZrOCl2溶液水解生成水合氧化锆颗粒的形成机理：四、ZrOCl2浓度和反应温度的影响
DOI：
10.1111/j.1151-2916.2002.tb00131.x
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
M. Ohgai
中科院分区：
文献类型：
--
作者：
K. Matsui;M. Ohgai
通过测定不同zrocl2浓度（0.1 ~ 0.4 mol/dm3）和反应温度（343 ~ 373 K）条件下水合氧化锆颗粒的形成速率、晶相、一次和二次粒径，探讨zrocl2浓度和反应温度对水合氧化锆颗粒形成过程的影响。化学分析和x射线衍射测试表明，在0.4 mol/dm3和≤363 K的合成条件下，合成的水合氧化锆颗粒与单斜晶氧化锆颗粒相似，只是晶体结构随着氯含量的增加而变化。随着zrocl2浓度的增加，单斜含水氧化锆颗粒的初级粒径减小，且与反应温度无关。在zrocl2浓度为0.1、0.2和0.4 mol/dm3时合成的水合氧化锆颗粒的二次粒径随反应温度的降低依次单调增大，先增大后减小，依次单调减小。利用Avrami-Erofeev方程，测定了氧化锆颗粒的速率常数k。测定的k值随着zrocl2浓度的增加和反应温度的降低而降低。通过k的Arrhenius图，确定了单斜相和高氯含量的含水氧化锆颗粒的活化能分别为387 ~ 396和249 kJ/mol。在此基础上，确定了初生颗粒的成核和晶体生长机制以及初生颗粒之间的硬聚集形成的二次颗粒的形成机制。
The formation rate, crystal phase, and primary and secondary particle sizes of hydrous zirconia particles produced under the hydrolysis conditions of various ZrOCl2concentrations (0.1–0.4 mol/dm3) and reaction temperatures (343–373 K) were measured to investigate the effects of ZrOCl2concentration and reaction temperature on the formation process. Chemical analyses and X-ray diffraction measurements revealed that hydrous zirconia particles synthesized under all of the hydrolysis conditions were similar to those observed in monoclinic crystalline zirconia, except that the crystal structure changed as the chlorine content increased under the synthesizing conditions of 0.4 mol/dm3 and ≤363 K. The primary particle size of monoclinic hydrous zirconia particles decreased as the ZrOCl2concentration increased and was independent of the reaction temperature. The secondary particle size of hydrous zirconia particles synthesized at ZrOCl2concentrations of 0.1, 0.2, and 0.4 mol/dm3 increased monotonously, first increased and then decreased, and decreased monotonously as the reaction temperature decreased, respectively. The rate constants (k) of the hydrous zirconia particles were determined experimentally by applying Avrami–Erofeev's equation. The determined k value decreased as the ZrOCl2concentration increased and the reaction temperature decreased. From Arrhenius plots of k, the activation energies for hydrous zirconia particles in the monoclinic phase and containing high chlorine contents were determined to be 387–396 and 249 kJ/mol, respectively. The nucleation and crystal-growth mechanisms of primary particles and the formation mechanism of secondary particles formed by hard aggregations among primary particles were determined based on the present experimental results.